, the economy comes to life. norfolk southern. one line, infinite possibilities. at tyco integrated security, we consider ourselves business optihow?rs. by building custom security solutions that integrate video, access control, fire and intrusion protection. all backed up with world-class monitoring centers, thousands of qualified technicians, and a personal passion to help protect your business. when your business is optimized like that, there's no stopping you. we are tyco integrated security. and we are sharper. >>> welcome back to this special edition of the "cnn newsroom." i'm fredricka whitfield here in atlanta. we'll get back to boston with wolf blitzer in a moment. overseas in london, runners in another marathon race are remembering the bombings in boston. take a look at this video from the bbc. huge crowd despite the concerns about safety. the london marathon went on as planned. 35,000 strong. extraordinary. participants observed a moment of silence to pay tribute to those killed and injured in boston. and in the wheelchair division in london, an ethiopian racer won for a second time.